In most instances, the production of crude oil from a subterranean reservoir results in the product being carried from the substrate, to the surface in the form of a multi-phase fluid stream. Usually the stream is comprised basically of the crude oil, and natural gas, together with water, which is normally contained in, or has been injected into the reservoir. Depending on the character of the latter, the upflowing production stream will embody varying amounts of reservoir gas. Functionally, the gas forces the stream upwardly, or is merely intermingled with the composite liquid stream to decrease its density and foster upward movement.
When the production stream is removed from an offshore reservoir, it is usually deposited into a separating facility. The latter allows a natural, gravity separation of the various stream elements in accordance with their densities. Such offshore fluid separating installations are typically found on a supporting vessel such as tanker vessels, tension leg platforms, or semisubmersible vessels.
It can be appreciated that such floating marine vessels, when in an offshore body of water, are subjected to an environment in which weather and sea play a major role. Thus, the vessel is frequently rocked with sufficient turbulence that the composite fluid will be sloshed through the separator apparatus tanks.
The problem of production stream separation becomes particularly critical in the instance of a horizontal separating unit. In the latter, the holding tank or tanks are disposed in a generally horizontal arrangement. This type of unit contrasts from a vertical unit which, as the name implies, takes the form of one or more upright tanks characterized by a minimal water/oil interface.
Among the common methods used for suppressing fluid motion within horizontal separators, is to employ some form of baffle or packing. This solution to alleviate or obviate movement has proven to be less than completely effective. For one thing, it seriously compromises the gravity separation mechanism. Further, it tends to reduce the overall magnitude of fluid movement to a cellular motion between the respective baffles. The quiescent liquid volume necessary to permit movement of oil and water droplets is still perturbed and porous baffles tend to set up turbulent and shear motion within the fluid to remix the oil and water.